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`39/16 : 5/8 - 7/16 : 5/8`
`=39/16 xx 8/5- 7/16 xx 8/5`
`=8/5 xx (39/16 - 7/16)`
`= 8/5 xx2`
`= 16/5`
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` 4/3 xx 9/8 - 4/3 xx 3/8`
`=4/3 -(9/8 - 3/8)`
`= 4/3 xx 3/4`
`=1`
\(a,\\ \dfrac{39}{16}:\dfrac{5}{8}-\dfrac{7}{16}:\dfrac{5}{8}\\ =\dfrac{39}{16}\cdot\dfrac{8}{5}-\dfrac{7}{16}\cdot\dfrac{8}{5}\\ =\dfrac{8}{5}\cdot\left(\dfrac{39}{16}-\dfrac{7}{16}\right)=\dfrac{8}{5}\cdot2=\dfrac{16}{5}\\ b,\\ \dfrac{4}{3}\cdot\dfrac{9}{8}-\dfrac{4}{3}\cdot\dfrac{3}{8}=\dfrac{3}{2}-\dfrac{1}{2}=1\)
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a) = (360 + 126 + 123) : 3 = 203
b) = (436 + 164 - 200) : 4 = 100
c) = (525 + 120 - 145) : 5 = 100
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Bài 4:
a: \(=\dfrac{11}{21}\left(\dfrac{7}{4}+\dfrac{5}{4}\right)=\dfrac{11}{21}\cdot3=\dfrac{11}{7}\)
b: \(=\dfrac{6}{13}\left(\dfrac{23}{14}-\dfrac{9}{14}\right)=\dfrac{6}{13}\)
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\(\Rightarrow x\times\left(\dfrac{9}{5}+\dfrac{6}{5}\right)=\dfrac{3}{4}\\ \Rightarrow x\times3=\dfrac{3}{4}\\ \Rightarrow x=\dfrac{3}{4}:3\\ \Rightarrow x=\dfrac{3}{4}\times\dfrac{1}{3}=\dfrac{1}{4}\)
\(\dfrac{9}{5}\times x+\dfrac{6}{5}\times x=\dfrac{3}{4}\)
\(x\times\left(\dfrac{9}{5}+\dfrac{6}{5}\right)=\dfrac{3}{4}\)
\(x\times3=\dfrac{3}{4}\)
\(x=\dfrac{3}{4}:3=\dfrac{3}{4}\times\dfrac{1}{3}\)
\(x=4\)
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a.\(\dfrac{2}{3}\times\dfrac{4}{9}+\dfrac{2}{3}\times\dfrac{5}{9}=\dfrac{2}{3}\times\left(\dfrac{4}{9}+\dfrac{5}{9}\right)=\dfrac{2}{3}\times1=\dfrac{2}{3}\)
b.\(\dfrac{7}{5}\times\dfrac{3}{4}-\dfrac{1}{2}\times\dfrac{3}{4}=\dfrac{3}{4}\times\left(\dfrac{7}{5}-\dfrac{1}{2}\right)=\dfrac{3}{4}\times\dfrac{9}{10}=\dfrac{27}{40}\)
c.\(\left(\dfrac{5}{6}+\dfrac{5}{8}\right)\times\dfrac{2}{3}=\dfrac{35}{24}\times\dfrac{2}{3}=\dfrac{35}{36}\)
a) 2/3 x 4/9 + 2/3 x 5/9
=2/3 x ( 4/9 + 5/9)
= 2/3 x 1
= 2/3
b, 7/5 x 3/4 - 1/2 x 3/4
= ( 7/5 - 1/2 ) x 3/4
= 9/10 x 3/4
= 21/40
c, ( 5/6 + 5/8 ) x 2/3
= 35/24 x 2/3
= 35/36
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4/9 x (3/5-1/5) +4/9 -7/5 x 4/9
= 4/9 x 2/5 + 4/9 x 1 - 4/9 x 7/5
= 4/9 x (2/5+1-7/5)
=4/9 x 0
=0.
tick mk nha
HT
4/9 x (3/5-1/5) +4/9 -7/5 x 4/9
= 4/9 x 2/5 + 4/9 x 1 - 4/9 x 7/5
= 4/9 x (2/5+1-7/5)
=4/9 x 0
=0.
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a) \(\dfrac{3}{5}\times\dfrac{17}{21}+\dfrac{17}{21}\times\dfrac{2}{5}\)
\(=\dfrac{17}{21}\times\left(\dfrac{3}{5}+\dfrac{2}{5}\right)\)
\(=\dfrac{17}{21}\times1\)
\(=\dfrac{17}{21}\)
b) \(\dfrac{15}{8}:\dfrac{5}{20}-\dfrac{7}{8}:\dfrac{1}{4}\)
\(=\dfrac{15}{8}\times\dfrac{20}{5}-\dfrac{7}{8}\times4\)
\(=\dfrac{15}{8}\times4-\dfrac{7}{8}\times4\)
\(=4\times\left(\dfrac{15}{8}-\dfrac{7}{8}\right)\)
\(=4\times1\)
\(=4\)
![](https://rs.olm.vn/images/avt/0.png?1311)
9/5 + 4/7 + 6/5 + 3/7
= ( 9/5 + 6/5 ) + ( 4/7 + 3/7)
= 3 + 1
= 4
9/5 + 4/7 + 6/5 + 3/7 = (9/5 + 6/5) + (4/7 + 3/7)
= 15/5 + 7/7
= 3 + 1
= 4
1/2 x 45/33 x 1/9 x 11/6 = (1/2 x 1/9) x (45/33 x 11/6)
= 1/18 x 45/18
= 5/2
A) =5
B) = 13440 pn nha
=5/4:(5/6+5/9+1/1)
=5/4:43/18
=45/86